62 SCIENCE PROGRESS 



special experimental conditions in a lysimeter, Howard and 

 Howard showed that water-logging of the soil might be of 

 more importance than phosphate supply, and Davis has 

 pointed out the necessity of remedying the deficiency in organic 

 matter which has been noted in many of these soils. This, he 

 recommends, should be dealt with by ploughing in sannai 

 {Crotalaria jiincea) as a green manure, or by combining this 

 with superphosphate treatment. The remarkable increase in 

 plant and seed yield brought about at Pusa by the addition 

 of leaf-mould has been demonstrated by Howard and Howard. 

 With regard to the development of wilt in khoonties, planters 

 attach special importance to the correct timing of the cutting 

 with regard to subsequent rainfall. This may either drown 

 out the stalks or promote such a rapid growth as to emphasise 

 the phosphate deficiency. 



From the foregoing brief sketch it may be seen that the 

 successful cultivation of indigo in Behar is beset with many 

 problems. It may be added, though, that in parts of Assam 

 a sandy, well-aerated soil rich in organic matter and in phos- 

 phates, combined with a liberal rainfall and the requisite 

 temperature, gives conditions very well suited to the growth 

 of Java indigo, so that heavy yields of plant rich in indican 

 are obtained ; wilt is unknown, and seed is well formed and 

 matured. Yields of ten maunds per acre can be obtained as 

 against a half to one and a half maunds of seed in Behar. A 

 falling off in seed was one of the first symptoms of soil deficiency 

 observed in Behar with this crop. 



Species and Varieties of Indigo. — ^The Natal-Java indigo 

 plant usually grown in Behar and Assam consists of a number 

 of varieties differing as regards their general habit both above 

 and below ground. Details of these may be found in the 

 final report of the Sirsiah Station, 191 3, in which Parnell 

 summarises the botanical work, and in the Pusa Memoir by 

 Howard and Howard, 1920. 



It must be mentioned that, after the introduction of the 

 Java plant, seed was obtained both from Indian-grown Java 

 plant and from Java. As indigo went out of cultivation by 

 the Dutch planters in Java, who, owing to the competition of 

 the synthetic dye turned their attention to sugar, the supplies 

 of seed could in time be obtained only from natives of Java. 

 When, owing to the wilt, the Behar crop of Java plant failed to 

 set seed, recourse was had to natives of Java for seed. But, 

 owing to crossing with wild forms in Java, it appears highly 

 probable that the resulting mixture of types was not the same 

 as was originally obtained from the Dutch planters. It has 

 been pointed out by Howard that this mixture contained 

 many of the deeper rooting forms which are not so well 



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